The present invention concerns a column construction or a boiling space in a distilling apparatus, comprising a pure vapor input connector, an input connector for water to be distilled, numerous heat exchange tubes within the column structure, a pure vapor removal connector, a condensate removal connector, and a connector for removal of water to be distilled which has not been vaporized.
Numerous types of distilling apparatus of the kind defined above are known in the art. The problems associated with energy economy have been solved in distilling apparatus now on the market, so that attention is presently directed to the quality of the distilled water.
The quality of the distilled water is influenced by the materials of the structures of the distilling apparatus, the structural details of the distilling apparatus, and, above all, by the mode of welding applied in producing such structures.
In quality considerations of distilled water, particular attention is presently paid to minor impurities, even molecular in order of magnitude, which are still able to enter through microscopic crevices in structures of distilling apparatus designs of the art.
Such microscopic crevices are formed, e.g., when the heat exchange tubes are affixed to the flanges. Particular mention may be made of biogenic bacteria, viruses, endotoxins, etc., which have a molecular weight even on the order of 10,000 to 500,000. Such impurities are extremely harmful, and may totally destroy the quality of the distilled water. It has not been possible to avoid this drawback in designs of the prior art.
In distilling apparatus presently known, the general principle of operation is that in the column of the distilling apparatus, pure vapor is introduced by the input connector, and feed water is conducted into a distribution space where the water enters the heat exchange tubes and runs down within the same. Especially susceptible points regarding formation of microcrevices are the junctures where the heat exchange tubes join the flange structures. In distilling apparatus designs of existing art, elimination of microcrevices has been attempted by applying the so-called expanding technique. Comparatively tight-sealing junctures are obtained by such a problem solution, however this method involves relatively high cost, while complete elimination of microcrevices cannot be achieved even with this method.